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The ability of influenza viruses from different hosts to bind to the intestinal epithelium of various birds (Anseriformes (Anatidae), Galliformes, Charadriiformes (sandpipers and sea gulls), Ciconiiformes (storks), Podicipediformes (grebes), and Gruiformes was studied. The composition of sialo-containing receptors on the epithelia was examined, by using lectins. Intestinal epitheliocytes of the Anatidae (Anseriformes) family was shown to have a low content of receptors binding both Sambucus nigra agglutinin (SNA) lectin specific to Siaalpha-6Gal, and Maackia amurensis agglutinin (MAA) lection specific to Siaalpha2-2Gal. Nevertheless, these cells well bound duck influenza viruses. The intestinal epithelium of Ciconiiformes, Podicipediformes, and Gruiformes well bound MMA lection, but avian influenza viruses weakly bound the latter. The intestinal cells of Gallinaceae bound both MMA and SNA lectins and avian and human influenza viruses. Thus, the composition of natural sialosides is different in various avian species whereas the receptor specificity of influenza viruses from various hosts reflects these differences. This can be accounted for by the differences in the ability of influenza viruses from different birds to break through the interspecies barrier, infecting mammals and human beings in particular.

The receptor properties of H1 and H2 influenza viruses (IV), isolated from duck, pig and man were studied by using the natural and synthetic sialoglycoconjugates. It was shown that viruses, isolated from different hosts, adapt themselves to the host cell receptors. The IV affinity was increasing to 6'sialy(N-acetyllactosamine) in proportion as amino acids (in positions 138, 190, 194 and 225), which are for avian IV, were increasingly replacing. Some of the porcine viruses display adaptation to the human receptor, i.e. 6'sialy(N-acetyllactosamine), however, all tested porcine influenza viruses, belonging to different evolution branches, acquired even more affinity to sulphated and fucozyled derivatives of 3'sialy(N-acetyliactosamine)-(Neu5AC alpha 2-3 g AL beta 1-4(fUC alpha 1-3)(6-sulfo)GlcNAc beta).

The receptor properties of influenza virus (IF) isolates/SSSR/90/77 are studied. The isolates are peculiar for losing glycosylation sites (GS) at the Asn131 receptor-binding region (GS131) after passaging in mice and at the Asn158 region (GS158) after cultivation in the presence of mouse serum. The loss of each carbohydrate residue increases the influenza virus affinity for carbohydrate chains with the terminal group Neu5Ac alpha 2-6Gal and reduces its affinity for Neu5Ac alpha 2-3Gal receptors. The effect is more pronounced in the GS158-depleted virus. Upon substitution of asparagine by aspartic acid, the electrostatic component of virus binding to the receptor is altered because of the increased negative charge on hemagglutinin. The virus receptor phenotype changes depending on the cultivation conditions. The isolate adapted to mice has higher affinity to mouse lung cell receptors, while the virus propagated in chick embryos in the presence of inhibitors has higher affinity to allantoic membrane cells.

In the process of the immunological approbation of several experimental batches of the triyalent subunit influenza vaccine Grippovac, the pronounced immunogenicity of the antigens of all strains contained in the vaccine was established; most of the vaccinees were found to retain sufficiently high antibody titers for a year, and the essential total increase of antibody titers was found to occur after a single booster immunization. The serological checking of the diagnosed cases of influenza among immunized and nonimmunized children, carried out in two boarding schools during the influenza epidemic in the winter of 1984-1985 provided the proofs of the high effectiveness of Grippovac in preventing viral influenza, types A and B: the decrease of influenza morbidity among the immunized children reached 79,5-67,2-66,5% and the total morbidity rate in influenza in these two boarding scholls dropped, on the average, 3,0-3,5 times.

Experiments were carried out to clarify the effect of swelling coefficients of various samples of the polycondensation anion exchange resin FAF in the C1 form on its sorption properties. The anion exchange resin was used to eliminate contaminating proteins and low molecular weight agents from the allantois fluid and liver cultured cells of pigs. Thermal treatment of the anion exchange resin increased the coefficient of its swelling, leaving the structure unchanged. The resin structure was controlled by electron microscopy and X-ray scattering of low angle. When the resin samples with the swelling coefficients of 3.5 and 4.0 were used, 30-40% of proteins, 50% of reducing agents and neutral carbohydrates and a small quantity of phosphorus were adsorbed.

55697 Ixodidae ticks of 35 species, belonging to 7 genera, were collected in Guinea in 1981-1983. Virological study of 29410 ticks was performed by intracerebral infection of newborn white mice. 49 viral strains were isolated. Authors identified 38 strains of the 8 following arboviruses: Dugbe, Bhanja, CGL-Congo (ecologically connected with ticks), blue tongue virus of sheep and Abadine (association with ticks was found for the first time), Kindia and Forekarya (the new viruses). Serological screening of cattle (by means of agar diffuse precipitation reaction) has demonstrated a wide distribution of isolated viruses in Guinea. Most active circulation was that of Abadine virus. Its peak was observed in the humid season, the period of Amblyomma variegatum imago domination on cattle, this tick being the main source and vector of the virus, as experimentally confirmed.